Maxine Waters
WASHINGTON, DC - MARCH 12: House Financial Services Committee Chairwoman Maxine Water (D-CA) questions Wells Fargo and Company CEO Timothy Sloan as he testifies before the committee in the Rayburn House Office Building (Photo by Chip Somodevilla/Getty Images)

Housing and Urban Development Secretary Ben Carson learned the hard way to respect his elders, when he tried to diss House Financial Services Chairwoman Maxine Waters (D-Calif.) in a scathing letter… and she clapped back.

READ MORE: Maxine Waters skips SOTU and drags President Trump: “He doesn’t know the rules of the game”

Carson took aim at Waters, writing that she lacked “basic manners” when addressing President Donald Trump about homelessness.

“My mother always taught me that people shouldn’t throw rocks, especially while they live in a glass house,” Carson wrote, according POLITICO, which obtained the note.

“Because of that wise lesson, I was a little surprised to read your hostile letter to President Trump regarding the record number of homeless Americans in California, particularly in your district.”

Waters, an outspoken Trump adversary, wrote the letter last month criticizing the Trump administration over its ideas to sweep homeless people off the street in California.

“Your shamelessness knows no bounds,” Waters wrote to Trump.

Carson entered the fray and added his two cents writing, “Shamelessness is a career politician of 30 years laying blame.”

“Shamelessness is allowing more than 55,000 Americans to live on the very streets they represent,” Carson added.

“To me, the most compassionate, obvious, and logical solution would be to get as many homeless Americans off the streets — with a roof over their heads — as soon as humanly possible,” he said.

“I have sent multiple letters to your office and requested numerous meetings, but each time you’ve refused,” Carson wrote. “Basic manners elude you, and it seems that instead of producing results, you’re more interested in producing cheap headlines at the President’s expense — like a true career politician.”

Waters hit back with a few choice words of her own. She responded to Carson on Wednesday, advising him that he should keep his outbursts under control.

READ MORE: Ben Carson’s hires staffer who wrote he had no problem with whites using the N-word

“Ben Carson is like a duck out of water and has been a complete failure at HUD. His basic philosophy is antithetical to his duties and HUD’s mission,” Waters told the Washington Examiner.

“If he is sincere in wanting to have a constructive, bipartisan conversation with me, he can start by providing substantive answers to the numerous questions posed in my Oct. 28 letter and public support for the Ending Homelessness Act.”

She added, “In the meantime, he should contain his tantrums and leave his mother out of this.”

Mother has spoken.